Issues at a Yorkshire abattoir operated by Karro Foods, one of the UK’s leading pork processors were so serious that company executives agreed to destroy 468 pig carcasses that had travelled through the facility on the day of the inspection.

One meat inspection source told the BIJ the incident was “very, very serious” and said in their experience the destruction of so many carcasses was “unheard of”.

The breaches, uncovered by officials from the United States Department for Agriculture (USDA), prompted the intervention of the UK’s Food Standards Agency and the Department for Environment, Farming and Rural Affairs. They wrote to their US counterparts to outline action taken to “ensure that these findings do not re-occur” and offer assurances UK meat inspection regimes were “robust”.

Both the FSA and companies involved took steps to review and tighten up procedures in the wake of the USDA findings, according to a letter from the UK’s chief vet, Christine Middlemiss.

At three of the four plants inspected (no hygiene breaches were identified at the fourth), USDA officials found food safety breaches that experts say, left undetected, could have increased the risk of consumers being exposed to contaminated or diseased meat if they hadn’t been detected. The breaches included:

Meat contaminated with faecal matter was found to have entered a production area processing food for human consumption.

Pig carcasses were declared fit for human consumption without being sufficiently inspected by veterinary staff.

Conveyor belts for cutting raw pork were found contaminated with debris - including fat and blood - from meat processed the previous day.

Such failings could potentially “all too easily” result in contaminated meat entering the food chain and making people ill, said Professor Erik Millstone, a public health expert from the University of Sussex. “Dangerous and prohibited materials were not removed from production lines.”

Kerry McCarthy MP, shadow secretary of state for Environment, Food and Rural Affairs until 2016, described the hygiene breaches as “disgusting” and said she would be seeking assurances from the FSA that appropriate enforcement action had been taken.

“It’s somewhat ironic, given that we are so concerned about a post-Brexit trade deal opening the door to US meat imports with lower food standards that it’s a US agency that has uncovered these violations,” she added.

Andrew is an award-winning investigative journalist specialising in food and farming issues. He is the co-founder of the ethical investigative agency Ecostorm and was editor of The Ecologist magazine between 2010 and 2012. His book, the Ecologist Guide to Food, was published in 2014. As well as reporting extensively for newspapers and magazines in the UK and beyond, he's co-produced films for The Guardian, Channel 4 News and KCET/Link TV, among others.

Emily Houghton is a Zoology graduate from Cardiff University. Emily has worked in livestock husbandry, and has written, conducted and assisted with research projects regarding the synthesis of welfare and productivity of free-range food species.